The Role of the Plant 9 



quantity eaten. We, therefore, cannot resist the con- 

 clusion that the bones, blood and flesh of this ox are 

 derived from what he eats. 



The plant does more than to supply building ma- 

 terial for the animal body. This living organism is 

 kept warm. No matter how cold the surrounding at- 

 mosphere, we find by the use of a thermometer that in 

 health the ox's temperature remains at about 101 F., 

 with but small variation. Just as the western farmer 

 obtained heat by burning corn in the fireplace, so does 

 the cattle -owner maintain the body temperature of his 

 animals at the necessary degree by supplying food to 

 be burned. The combustion is not so rapid as occurs 

 in the fireplace, still the changes are the same but more 

 slowly carried on. 



Food not only builds the ox and warms him, it 

 furnishes him with motive power. The energy which 

 the plant acquires during its time of growth is, through 

 his vital processes, transformed in part into motion. 

 The animal is a living mechanism, a combination of 

 muscles and levers which are moved not by means 

 of a spontaneous internal generation of energy, but 

 through a supply from without, the energy stored in 

 the plant. 



If we use the plant for fuel we get heat alone; if 

 we feed it to the animals we get heat, motion and the 

 production of other forms of matter that have a rela- 

 tively high commercial value. In the first instance 

 the plant substance, except the mineral portion, is 

 wholly broken up into simpler compounds which in 

 unseen gaseous forms escape from our possession, the 



